Culture Technique of Crucian Carp Variety Xiangyun Crucian Carp

Xiangyun crucian carp is a kind of triploid crucian carp successfully cultivated by Professor Liu Yun of Biology Department of Hunan normal University and Xiangyin Donghu fishing ground by using the technology of cell engineering and sexual hybridization. its male parent is tetraploid fish referred to as "gene reservoir fish", and its mother is Japanese white crucian carp. Xiangyun crucian carp is a high-tech product of bioengineering, and its theoretical significance and application value are in a leading position at home and abroad. 1. Xiangyun crucian carp seed production technology Xiangyun crucian carp seed production process is as follows: 2N cell engineering technology 4N (gene bank fish) × 2N (Japanese white crucian carp) male parent sexual hybrid female parent 3N (Xiangyun crucian carp) Xiangyun crucian carp has its own sterility and fast growth rate. Xiangyun crucian carp has a wide diet, strong disease resistance, tolerance to low oxygen and low temperature, easy to catch and other excellent characters, and the meat is delicate and delicious, so it is suitable for fishing. The fish is suitable for culture in ponds, lakes, reservoirs, rice fields and cages. Under general pond conditions, mixed culture can produce 60 kilograms per mu, and monoculture can produce 500 kilograms and 800 kilograms of fish per mu. The net output of cage culture is 50kg to 90kg per square meter. 2. Biological characteristics: Xiangyun crucian carp is a complete somatotype of crucian carp. LDH and EST isozyme detection and mtDNA analysis show that Xiangyun crucian carp is inherited from its female parent, but it also has the gene expression of Xiangjiang wild carp, crucian carp, Hunan crucian carp and tetraploid fish, so there are the following differences between Xiangyun crucian carp and common crucian carp: 1. The shape difference between Xiangyun crucian carp and other crucian carps. Xiangyun crucian carp is similar to ordinary white crucian carp in appearance, but its body shape is better than other species, because of sterility and small proportion of gonads, so it has less internal organs, smaller abdomen, thicker back muscle and slimmer figure than other crucian carp species. The scales on the back of Xiangyun crucian carp are often arranged in some disorder (there are few other crucian carps), and the lateral scales are generally in the range of 30 to 32. 2. Xiangyun crucian carp has abnormal gonad development and can not reproduce itself: Xiangyun crucian carp is triploid crucian carp, which can not reproduce, and there is no sexual chase, so it can be released in any culture water area, which will not cause other crucian carp species resources to be mixed, nor will it lead to the decline of commercial fish quality due to overreproduction. 3. Xiangyun crucian carp grows fast and is not limited by sexual maturity. In general, the early sexual maturity of crucian carp affects the growth rate and limits the growth of individuals. Xiangyun crucian carp not only has obvious hybrid growth advantage, but also because of sexual sterility, the nutrition intake is completely used for growth, and individual growth will not be limited by sexual maturity. The growth rate of Xiangyun crucian carp was more than twice that of its female parent (Japanese white crucian carp) and 3-5 times that of common crucian carp, and the maximum growth weight of fry could reach 0.5 kg in the same year. The average individual of adult fish cultured in spring slices can reach 0.5 kilograms, and the largest individual can reach 1.5 kilograms. 4. Xiangyun crucian carp has strong resistance. The hybrid advantage of Xiangyun crucian carp is also shown in its strong resistance to the harsh natural environment, mainly in the following aspects: (1) strong disease resistance and wide adaptability. After years of promotion, it has been cultured in 20 provinces and cities in China, all of which can adapt to the local environment, and there are no reports of heavy losses caused by infectious diseases. (2) strong tolerance to hypoxia. It can still grow well in the environment of high stocking density and small water body (for example, 200 fish per square meter in cage culture, the yield is up to 57 kg / square meter). When there was "pan-pond" hypoxia in pond culture, grass carp, silver carp and bighead carp all died in varying degrees, while Xiangyun crucian carp rarely died. (3) good resistance to low temperature. In Hunan, it can feed all the year round, and it can still feed and grow when the water temperature is 10 ℃ (four big fish have stopped feeding). 5. The diet is wide and the feed coefficient is low. Xiangyun crucian carp not only has a wide diet and tolerance to coarse bait, but also maintains the characteristics that the parent Japanese white crucian carp can eat part of the plankton, and the nutrition is completely used for growth, so the feed utilization rate is higher than that of other crucian carp. 6. It is easy to catch. Xiangyun crucian carp cultured in ponds do not "drill mud", and the net fishing rate can reach about 80%, unlike ordinary crucian carp that need "dry ponds" for listing. 7. Good quality. Xiangyun crucian carp meat delicate, delicious meat to maintain the flavor of crucian carp, while less fine thorns, less viscera, more edible parts, and large, high glutamate content in muscle, better than the general crucian carp taste, deeply welcomed by consumers. Seedling cultivation 1. Summer flower cultivation: although Xiangyun crucian carp has obvious hybrid advantage, the summer flower cultivation stage happens to be from April to early May, which is low temperature, rainy and bad climate, so it brings great difficulties to seedling production. In addition to operating strictly in accordance with conventional cultivation procedures, special attention should be paid to the following points: (1) strict pond cleaning and disinfection. The seedling ponds of Xiangyun crucian carp should be thoroughly disinfected, the wild miscellaneous fish and enemy pests should be cleared clean, and the incoming water should be strictly filtered to prevent new enemies from entering. Because the temperature is low, the growth rate of fish fry is relatively slow, while wild miscellaneous fish and enemy organisms multiply very fast, and a small number of wild miscellaneous fish that escape the net, such as wheat ear fish, wild crucian carp, grass shrimp and so on, will reproduce rapidly, which will seriously threaten the survival rate of Xiangyun crucian carp seedlings. when serious, it often causes "the whole army to perish". At the same time, in low temperature weather, the medicine of clearing pond disappears slowly, so the toxicity of pond water should be carefully tested before seedling. (2) adhere to the fry fertile water into the pond. Because Xiangyun crucian carp has strong tolerance to hypoxia, pre-fertilizing a pool of "good water" plays a significant role in improving the survival rate of summer flowers, avoiding the disadvantage that Xiangyun crucian carp can not feed fully because of low temperature, overcast and rain, slow reproduction of plankton in the fry pond. In order to improve the quality of water, we should pay attention to being "fat and cool" and prevent the emergence of "old water" and "white water" that breed in large numbers of large fleas. (3) monoculture is dominant, and the density is suitable. Xiangyun crucian carp summer flower should not be mixed with other seedlings, and the stocking density should be sparse and not dense, with 8 ~ 100000 seedlings per mu. It is best to sparse, with an income of 40,000 to 60,000 per mu, about 3 cm of summer flowers can be bred in about 15 days, and then free up the pond to cultivate the summer flowers of the four big fish, which can improve the utilization rate of the seedling pond. If there are special circumstances, the stocking density must be increased, and the ponds should be divided in time after 8 to 10 days. (4) replenish the concentrate in time. Xiangyun crucian carp seedlings used plankton as bait in the early stage, so as long as fertilizing to keep the water color. After 8 days and 12 days in the lower pond, the feeding habits of fish fry begin to differentiate. When fish fry begin to "show their belly", concentrate such as rice bran and vegetable cake powder should be added in time. If it is found that fish fry swim crazily along the edge of the pool, there is a lack of concentrate, and more concentrate should be put along the edge of the pond, otherwise it will seriously affect the survival rate. As long as we pay attention to the characteristics of Xiangyun crucian carp seedlings and careful management, serious diseases will not occur in the summer flower stage, and the survival rate can reach more than 80%. 2. Fish fingerling cultivation. In addition to directly using summer flower fry to cultivate adult fish, Xiangyun crucian carp summer flower should be recultivated into 40g and 50g species, which can be cultured as adult fish in winter or spring next year, which can make full use of the advantage that Xiangyun crucian carp growth is not affected by sexual maturity. There are mainly the following ways to cultivate fish species. (1) monoculture. Xiangyun crucian carp monoculture pond should not exceed 15 mu, the water depth is in the range of 1.5 to 2.5 meters, and the drainage and irrigation is convenient. The pond should be strictly cleared and disinfected before stocking, and according to the pond conditions, 6000 to 10,000 pieces per mu can be put in, which can be matched with 1 000 silver carp and bighead carp summer flowers, or 200 spring slices, and about 5% grass and carp species should be put in depending on the situation. In addition to feeding regularly and quantitatively every day, new water should be injected frequently to keep the oxygen content in the pond water in a normal state (40.06 mg / L), and pay attention to prevent the escape of fish species (Xiangyun crucian carp has the habit of reverse water). After 6 months of culture, it can reach 40kg / tail, the general yield per mu can reach 300kg / mu, and the pond with good management conditions can reach 500kg. (2) mixed culture. In general, spring ponds can mix Xiangyun crucian carp with summer flowers as long as they are not mixed with other species of carp. Generally, 300 million and 500 animals per mu are stocked. In addition to feeding according to conventional breeding methods, concentrate should be properly supplemented at the turn of autumn and winter to meet the bait needs of Xiangyun crucian carp. The yield of Xiangyun crucian carp can be increased by 50kg to 70kg per mu. (3) cage culture. In the case of a large number of spring slices of Xiangyun crucian carp and lack of fish ponds, using the characteristics of Xiangyun crucian carp with filter feeding performance, dense culture and disease resistance, suitable for commercial feed, the cage culture of Xiangyun crucian carp is effective. Cages should be placed in eutrophication, micro-running water, shelter from the wind to the sun of the reservoir bay, lake branches and other large water surface, the mesh size should be matched with the specifications of fish species. Every day adhere to bait and box cleaning, pay attention to the prevention of parasitic diseases. With 400,500 summer flowers per square meter, the size of fish can reach 40,60g in 4 months, and the survival rate can reach 90%. At the same time, the effect of raising Xiangyun crucian carp adult fish in cage is better than that of grass carp or other carp. Generally 28 square meters of cage put 3 000 or so 50 grams of fish species, culture for 6 months, up to 400 grams 600 grams of adult fish. The net profit of each cage can reach about 4,000 yuan, and the management is convenient. 4. Adult fish culture techniques 1. Xiangyun crucian carp culture in the suburbs of Beijing: in 1998, adult fish culture experiments were carried out in four fishing grounds in Tongzhou, Pinggu, Haidian and other districts and counties on the outskirts of Beijing. 153000 Xiangyun crucian carp summer flowers were purchased from Changsha pilot test base of Hunan Science and Technology Commission on May 10-20, 1998 and released from the pond in the middle of October. The adult fish test area is 26.7mu, with a total yield of 13,435kg, with an average yield of 503kg per mu, including Xiangyun crucian carp 440kg, flower silver carp 63kg, Xiangyun crucian carp survival rate 93.6%, average specification 193g / tail, feed coefficient 1.28and input-output ratio 1 ∶ 1.26. Through the culture experiment in 1998, Xiangyun crucian carp has the following characteristics: (1) the growth advantage is obvious. Xiangyun crucian carp has a faster growth rate, which is 1.5 times faster than that of common crucian carp. (2) the feed coefficient is low. During the culture period, the average feed coefficient was 1.2-1.5. (3) strong disease resistance and tolerance to hypoxia. During the culture period, no large area of fish disease was found in all the tested units. For example, the stocking density of Liangjiadian fishing ground in Haidian District reached 8600 fish / mu, no fish disease occurred, and the aerator was only opened for a few days in the high temperature season during the culture period, indicating that the fish has a strong ability to tolerate hypoxia. (4) resistant to low temperature. According to the law of culture in Beijing, crucian carp and mackerel have stopped feeding around the middle of October, but the fish can still be fed in late October when the temperature is low, thus prolonging the growth period. 2. Several problems should be paid attention to in the process of Xiangyun crucian carp culture. (1) intensive culture of Xiangyun crucian carp is beneficial to intensive culture, but attention should be paid to the proportion of silver carp and bighead carp. There are 250 to 300 silver carp and 25 to 30 silver carp per mu, and the ratio of silver carp to silver carp is basically controlled at 10 ∶ 1. In the process of breeding, do not match grass, carp and other fish with strong grazing ability, so as not to affect the feeding and growth of the main fish. (2) Xiangyun crucian carp has the characteristics of fast feeding, large area and short time, so the feeding times and feeding area can be increased appropriately every day. In the high temperature season, 5-6 times a day (depending on the water temperature and weather conditions), fishing grounds with conditions can be fed by automatic bait feeding machine to increase the feeding area. (3) to strengthen the feeding management in the early stage of stocking, Xiangyun crucian carp has strong group feeding ability. The key to forming this feeding habit lies in the domestication of seedlings within one month, and the method of concentrating first and then dividing ponds should be followed. For example, a total of 60,000 summer flower seedlings were raised in Liangjiadian fishing ground in Haidian District, which were first fed with broken materials in a 5-mu pond, and when they grew to 25 grams per tail, the density decreased after the pond, but did not affect the feeding of Xiangyun crucian carp group. (4) stocking density according to each culture unit, the smaller the density of Xiangyun crucian carp is in adult fish culture, the slower it is to rise and grab food, so the suitable stocking density of adult fish is 3 000 to 3 500 per mu.